doc/go1.4: encoding/csv

CC=golang-codereviews
https://golang.org/cl/162140043

doc/go1.4.txt

@@ -26,6 +26,7 @@ crypto/tls: add support for ALPN (RFC 7301) (CL 108710046)
 crypto/tls: support programmatic selection of server certificates (CL 107400043)
 flag: it is now an error to set a flag multiple times (CL 156390043)
 fmt: print type *map[T]T as &map[k:v] (CL 154870043)
+encoding/csv: do not quote empty strings, quote \. (CL 164760043)
 encoding/gob: remove unsafe (CL 102680045)
 misc: deleted editor support; refer to https://code.google.com/p/go-wiki/wiki/IDEsAndTextEditorPlugins instead (CL 105470043)
 net/http: add Request.BasicAuth method (CL 76540043)